Advancements in semiconductor technology have led to the production of large scale integrated circuits which have brought about a revolution in the electronics industry. Microelectronic components are now widely used in the production of a variety of electronic devices (e.g. portable computers, calculators, watches, cordless telephones, radios, tape recorders, security systems ). Development of such portable electronic devices has brought about the evolution of batteries as miniature power supplies. This new generation of batteries must produce higher energy per unit volume and superior discharge characteristics as compared to traditional batteries.
The technology related to thin solid state batteries in particular, is being increasingly developed. Typically this type of thin battery is constructed with an alkali metal anode, a non-aqueous electrolyte, and cathodes of nonstoichiometric compounds. Lithium is most often used as an anode material because it has a low atomic weight and is highly electronegative. Such thin batteries have a high energy density, a long shelf life and operate efficiently over a wide range of temperatures.
In the past thin batteries have been manufactured by forming and assembling the anode, electrolyte, and cathode of a battery cell as separate components. This is a relatively labor intensive procedure that involves the intricate assembly of a number of discrete components. In particular, the stamping and handling of individual discs of lithium is costly and difficult, because lithium is expensive and highly reactive.
This has led to the development of continuous manufacturing processes in which the components of a thin battery are constructed using polymeric films. Such thin polymer batteries may include anodes, electrolytes and cathodes formed as a continuous film of a polymeric material. As an example, U.S. Pat. No. 4,621,035 to Bruder, describes a lithium battery that includes a lithium anode formed by laminating lithium to a conductive polymer.
These polymer battery components are typically manufactured by extruding or drawing down suitable materials, such as lithium, onto a flexible polymeric material. In general, this is a relatively complex manufacturing technique which requires relatively complicated and expensive manufacturing equipment. Furthermore, many of the difficulties in manufacturing such polymer batteries are related to handling and assembling the lithium anodes, the cathodic polymers and the electrolytic polymers. These problems are compounded because most prior art manufacturing procedures typically involve the formation of one battery cell at a time.
The present invention is directed to improved polymeric battery structures and improved methods for assembling such polymeric batteries. These improvements lower the manufacturing costs, increase the manufacturing efficiencies and provide improved batteries.
Accordingly, it is an object of the present invention to provide improved polymeric battery structures and particularly improved polymer-lithium batteries. It is a further object of the present invention to provide improved methods for manufacturing polymeric batteries. It is a further object of the present invention to provide improved battery structures that can be manufactured in multiple units and then singulated into individual batteries. It is yet another object of the present invention to provide improved thin polymeric batteries that are high in energy, reliable, light weight and relatively inexpensive to manufacture.